U.S. Pat. No. 3,397,993 to Strong is directed to a process for preparing frozen french fried potato segments which is said to enable the preparation of a final product, after a short finish fry, that closely simulates french fried potatoes prepared from fresh potatoes. According to the disclosure, potatoes are initially peeled, trimmed, cut into segments and washed. The individual segments are then blanched in hot water or steam until they become translucent but without blanching substantially beyond translucency. The disclosure points out that the sloughing of solids evidences overblanching. The blanched potato segments are then dehydrated for a product weight loss of about 20 to about 30% of their initial weight, immersed in a deep-fat fryer for from about 15 to about 60 seconds and are then frozen.
Strong indicates that, even after long periods of storage, the frozen potato segments can be finish fried rapidly to produce french fried potato strips of high quality, substantially identical to french fries produced from raw, unfrozen potatoes. Unfortunately, it has been our experience that french fried potatoes, whether prepared in the manner suggested by Strong, or from raw, unfrozen potatoes, lose their desired crispness after a relatively short period of time and become undesirably soggy.
During peak periods in high-volume fast-food restaurants, crispness retention can be controlled adequately by good management of the rate at which the french fries are finally fried. However, the best management plan requires close supervision and, even then, is susceptible to breakdown. Moreover, during periods of less than peak demand, the internal moisture within the previously fried fries is given sufficient time to migrate into the crisp outer surface of the fries to render them soggy. Thus, the restaurateurs' desire to meet immediate demands for crisp french fries must be tempered by the practical consideration of unacceptably high levels of products which must be discarded. And, diners who choose to take out their orders often end up with french fries which have lost their crispness.
Wilder, in U.S. Pat. No. 3,649,305 also discloses a process which is said to enable the preparation of frozen french fried potatoes which, when finish fried by the final user or retailer, will closely simulate french fried potatoes prepared from fresh potatoes in color, texture, flavor and odor. According to the disclosure, the potatoes are first peeled, trimmed, cut into french fry size strips and washed. The strips are then immersed in a water solution containing a commercially acceptable discoloration-inhibitor, dehydrated without prior blanching to reduce the weight by from about 10 to about 30%, and then blanched for 71/2 minutes. After blanching, the strips are then par-fried and frozen. While improvement in color retention is asserted, there is no indication that the product produced by Wilder has better texture initially or retains it any longer than french fried potatoes prepared from freshly-cut, raw potatoes.
Canadian Patent No. 900,266 to Saunders discloses a process which is again said to result in a finally fried product which simulates in color, quality, texture, flavor and taste, french fried potatoes prepared directly from fresh potatoes. Saunders discloses the conventional preliminary steps, including sugar adjustment for color control. No blanching is disclosed, but in two examples the pieces are dipped in heated (170.degree.-180.degree. F.) treatment solutions for about 1 minute. Thereafter the strips are partially fried to reduce the weight of the strips by about 20% prior to a dehydration step which results in a further weight reduction of from about 5 to about 20%. Following dehydration, the potato strips are subjected to a second frying step and frozen. Again, no improvement in crispness retention is disclosed.
The problem of retaining crispiness is addressed in U.S. Pat. No. 3,391,005 to Babigan and U.S. Pat. No. 4,254,153 to Ross et al. According to Babigan, a raw potato is cut into elongated strips having a plurality of thin parallel ribs of defined dimensions. These ribs enable the formation of a thicker, crisper crust by virtue of their shape. While Babigan discloses that the product can be frozen, there is no specific disclosure with regard to processing, such as blanching, necessary to prepare a high quality product from his cut raw potato strips.
Ross et al, in U.S. Pat. No. 4,254,153, discloses a process for preparing frozen par-fried potatoes which, when finish fried, are said to have a mealy internal core surrounded by a crisp surface which remains crisp and rigid for extended periods of time after frying. According to the disclosure, potatoes which have been peeled, trimmed, cut into strips and blanched for from 2 to 15 minutes to partially cook the potato pieces (Col. 2, l. 67), are subjected to a two-stage drying procedure. The first drying stage exposes the strips to high velocity ambient air to reduce their weight by about 8 to 15%. The second drying stage subjects the pieces to circulating heated air to further reduce the weight of the strips by an additional 8 to 15%. After drying, potato strips are then maintained in a quiescent state for a short period of time to permit equalization of the moisture distribution in the strips and are then par fried and frozen. According to Example 1, a 7-8 minute blanch at 181.degree. F. is followed by the two-stage drying procedure which takes a total of about 27 minutes, thus greatly increasing processing time from that which is conventional.
In U.S. Pat. No. 3,881,028 to Capossela, Jr. et al, there is disclosed a process for preparing a rehydrateable deep-fat fried potato product. According to this disclosure, potato pieces are preliminarily processed in conventional fashion, including blanching for 1 minute, and then heated by microwave energy to partially gelatinize the starch therein prior to deep-fat frying and heating to effect dehydration. The treated pieces are said to be shelf-stable without refrigeration and can be rehydrated by soaking in water and heating. Capossela Jr. et al disclose that it is possible to provide a crispier shell on the product if, after blanching and quenching in cold water, the potato pieces are soaked in a sodium chloride solution heated to about 180.degree. F., followed by washing again with cold water. There is no indication given by Capossela as to the effect of this cold-water-quenching/hot-salt-water/soaking/cold-water-quenching on product color. In any event, the teachings are not directed to a frozen, par-fried potato product and inherently produce a product which is less crisp than even products prepared from freshly-cut raw potatoes.
Similarly, U.S. Pat. No. 3,518,097 to Menzi is directed to dehydrated french fried potatoes. The disclosure states that a potato is fully cooked and then freeze-dried. Several techniques are suggested for increasing the drying rate after full frying and freezing. Among these are pressure cycling and puncturing. The resulting products must be rehydrated prior to heating and serving and will lack the textural quality of ordinary french fries.
In U.S. Pat. No. 3,934,046 to Weaver et al, a process is disclosed which is said to enhance texture, maintain flavor, and prevent darkening of fried potato products. As part of their disclosure, Weaver et al indicate that leaching raw potato pieces with hot water prior to frying has several disadvantages, including serious impairment of texture and flavor. According to their disclosed process, preliminarily prepared raw potato pieces are pre-fried first and then leached by contact with water. Weaver et al disclose that, following the application of these critical steps, the treated pieces may be subjected to any of various procedures, depending upon the final product desired. For preparing french fried potatoes, the examples indicate that the potato strips are frozen for later finish frying or are further fried prior to freezing for final preparation by oven baking.
There is a present need for simple and effective process improvement which would enable the preparation of fried, frozen potato products which would provide a moist, tender interior and at the same time retain their crisp outer texture for extended periods of time, especially when coupled with improved color control and efficient use of processing time and energy expenditure. There is a further need for such a process which would enable these desirable attributes to be achieved in frozen products which could be prepared for consumption by heating in a conventional or microwave oven.